Ceramic plates are known to stop high-velocity 5.56mm rounds including the green tip 62gr SS109. Don't get stuck with a Lightweight Polyethylene or other NIJ Level III inserts where fast 5.56mm rounds can slice right through. The NIJ Level III Standard protects the user from the bigger 7.62x51mm round, however, they can have a hard time stopping the thinner and faster 5.56mm round. With a Ceramic core The RTS Active Shooter Kit features protection from larger 7.62x51mm as well as faster 5.56mm round.